The Science Journal of the American Association for Respiratory Care
Background: The use of noninvasive ventilatory support has gained popularity over the last decade. The technique has been shown to decrease work of breathing and improve the ventilatory status of patients in acute respiratory distress (ARD) of cardiac, pulmonary, or neurologic origin. This study addresses the use of Bi-level PAP in the emergency department (ED) of an inner-city tertiary referral center on patients presenting with a primary diagnosis of CHF resulting in ARD. The aim is to evaluate the impact of Bi-level PAP on arterial blood gases, oxygen requirements, hospital admission (regular nursing floor vs intensive care unit), and avoidance of intubation. Method: The sample was comprised of 12 patients presenting to the ED with a primary diagnosis of CHF. Separate data collection sheets were utilized for all patients placed on the bi-level PAP system. Patients were assessed and rated on their intensity of sensation using a modified Borg Dyspnea Category Scale with 0 being nothing at all and 10 being maximal. The patients were managed by the physician and respiratory therapist in the ED with bi-level PAP settings adjusted to patient tolerance. Inspiratory Positive Airway Pressure/Expiratory Positive Airway Pressure (IPAP/EPAP) were set for patient comfort, ABG/saturation, and control of ventilation. Averages were 15/7 respectively. All patients were in the spontaneous/timed (S/T) mode with a % IPAP of 33. Breaths/minute were set two to five below the patient's spontaneous rate. All patients had continuous ECG and pulse oximetry monitoring.
Results: Table 1 presents arterial blood gas (ABG) mean with ranges in parenthesis and dyspnea index. Table 2 presents the FiO2/PaO2 relationship before and after bi-level PAP. Patients requiring 100% before, achieved a higher PaO2 after the initiation of treatment despite the machines ability to deliver an average FiO2 of 86% with a bleed-in at 10-15 lpm. Intubation was required in two (16%) of the patients. The remaining 10 (83%) were successfully managed throughout their hospital stay with bi-level PAP. Five (42%) were admitted to an intensive care unit; seven (58%) went to a regular nursing floor. Conclusion: Bi-level PAP decreased the work of breathing and improved the ventilation of patients presenting to the ED with a primary diagnosis of CHF.
|Table 1: ABG / Dyspnea Index|
|Before (n=12)||After (n=12)|
|pH: 7.23 (7.08-7.32)||pH: 7.32 (7.13-7.37)|
|PaCO2: 65 (33-88)||PaCO2: 53 (31 - 94)|
|PaO2: 62 (42-102)||PaO2: 76 (56 - 174)|
|% Sat: .84 (.68-.95)||% Sat: .91 (.87-.99)|
|Dyspnea index: 7||Dyspnea index: 3|
|Table 2: FiO2/PaO2|